The constant volume fuel/air cycle is used as a standard of comparision because it represents an upper limit of 100% efficiency. Compared to this ideal cycle, a typical four-stroke internal combustion engine is 20% less efficient, turning 80% of the available thermal energy in its fuel into work, during the expansion stroke. The twenty percent (20%) of lost energy is divided between heat loss (12%); time loss (6%) and exhaust blow-down loss (2%). Heat loss is heat transferred to the coolant during the expansion stroke. Time loss is piston motion during combustion. Exhaust blow-down loss is due to the opening of the exhaust valve (or port) before bottom dead center of the expansion stroke in order to minimize exhaust stroke loss.
The invention operates approximately 8% closer to the ideal thermal cycle. The invention utilizes true constant volume combustion (There is no piston motion during combustion) to eliminate time loss. Expansion continues all the way to bottom dead center without early blow-down to eliminate exhaust blow-down loss.
The invention is inherently 8% more efficient in the utilization of its fuel, resulting in substantial fuel savings.
In addition, an integral exhaust blow-down nozzle, in the rotor of the invention, captures kinetic energy that is released as the cylinder pressure reduces to the pressure of the exhaust system, before the exhaust stroke begins. No valve overlap period at the end of a more complete exhaust stroke results in no dilution of the fresh mixture on the next stroke by any residual gas fraction.
Other features include the elimination of any separate cam shaft, the elimination of all timing gears and simplicity of construction resulting in low manufacturing costs and ease of maintenance.